Citric acid effect on body chemistry pH

I see a lot of quacky sites about acid/alkaline body chemistry claiming that lemon juice and orange juice make the body alkaline. They both contain citric acid, orange juice also has lots of potassium... I cannot think of any mechanism whereby citric acid would somehow cause a persons body to become more alkaline. The theory is that every food when burned forms either an alkali or acidic ash, and this ash has an effect to alkalize or acidify the body, not just the blood. I can't find any evidence that citric acid alkalizes anything although sodium citrate is an antacid.
I can't find anything online except for these sites that claim it does alkalize the body...

Does citric acid really alkalize the body or blood? If so by what mechanism?

Staff: Mentor

Quackery squared.

I am not sure about biological details, there can be some additional things that I am not aware of. But in general pH of the body is maintained by very effective mechanisms that don't allow it to change by more than several hundreds of pH unit, no matter what we eat. That's what homeostasis is about. Blood pH is kept between 7.35 and 7.45.

My wife came to me with this and we had a long discussion about it (mostly me beating my head against a wall), imo, this is a classic case of quacks misinterpreting and misrepresenting basic chemistry.

Acid is acid, they acidify, bases are alkali, they alkalise.
When an acid is alkalised it can form products which are alkalising, but in the process it reduces alkalinity.
In the case of Citric Acid, when alkalised it can form citrates which do play a role in the body, primarily as an oxidant of fats/proteins/carbs. Fundamentally though, it was alkalised, so it reduced alkalinity, it acidified the solution, what is left over can still be alkaline (in pH), no problems there (so long as there was sufficient alkalinity), but citric acid is not alkalising in itself, it's an acid.
That's where I think they've gotten messed up, sure, it forms products that can alkalise...but they only did that by being alkalised (and therefore reducing alkalinity) in the first place.
adding acid can only acidify.